Towards a generic model for object-oriented information system modelling

With the proliferation of object-oriented methods for information systems design, and the terminology used by each one, an intermediate step is indispensable in the transition between the design and the different implementation environments. Regardless of any method, this step aims at the unification of all concepts in a generic model called MGCO2.     

Human aspects in object-oriented design: an assessment and a methodology

Object-oriented design has attractive features, but using an object-oriented technique does not necessarily guarantee a good design. In this paper an assessment is made which is concerned with human aspects in object-oriented design. Particularly, the important role of user's mental models in object-oriented design is emphasized. The relationship between analogical reasoning and software reuse is examined. To support the assessment in regard to human aspects, some methodological considerations are outlined, which are further examined through case studies.     

Human aspects in object-oriented design: an assessment and a methodology

Abstract

Object-oriented design has attractive features, but using an object-oriented technique does not necessarily guarantee a good design. In this paper an assessment is made which is concerned with human aspects in object-oriented design. Particularly, the important role of user's mental models in object-oriented design is emphasized. The relationship between analogical reasoning and software reuse is examined. To support the assessment in regard to human aspects, some methodological considerations are outlined, which are further examined through case studies.     

Implementing a user interface management system for existing applications using an object-oriented database tool

Numerous engineering application systems have been developed over the past twenty years, and many of these applications will continue to be used for many years to come. Examples of such applications include CAD Systems, finite-element analysis packages and inspection systems. Because many of these applications were developed before graphical workstations became available, they often have simple command-line user interfaces. Thus, there is a need for a graphical user interface management system (UIMS) that can be used to build point-and-click style interfaces for these existing engineering applications. In this paper we describe such a UIMS, and discuss its implementation using an object-oriented database tool. This UIMS allows users to create and modify user interfaces by editing graphical representations of the interfaces, thus eliminating the need to write code to build or modify an interface. The UIMS is implemented using an object-oriented database tool to take advantage of the data manipulation and storage management capabilities it provides. This approach reduces both the quantity and complexity of the code needed to implement the UIMS. It also allowed the UIMS to be implemented in a minimal amount of time.     

Enhancing river model set-up for 2-D dynamic flood modelling

Flood hazard mapping is a topic of increasing interest involving several aspects in which a series of progress steps have occurred in recent years. Among these, a valuable advance has been performed in solving 2-D shallow water equations in complex topographies and in the use of high resolution topographic data. However, reliable predictions of flood-prone areas are not simply related to these two important aspects. A key element is the accurate set up of the river model. This is primarily related to the representation of the topography but also requires particular attention to the insertion of man-made structures and hydrological data within the computational domain. There is the need to use procedures able to 1) obtain a reliable computational domain, characterized by a total number of elements feasible for a common computing machine, starting from the huge amount of data provided by a LIDAR survey, 2) deal with river reach that receives significant lateral inflows, 3) insert bridges, buildings, weirs and all the structures that can interact with the flow dynamics. All these issues have large effects on the modelled water levels and flow velocities but there are very few papers in the literature on these topics in the framework of the 2-D modelling. So, in this work, attention is focused on the techniques to deal with the above-mentioned issues, showing their importance in flood mapping using two actual case studies in Southern Italy. In particular, the simulations showed in this paper highlight the presence of backwater effects, sudden and numerous changes in the flow regime, induced by the detailed river model, that underline the importance of using 2-D fully dynamic unsteady flow equations for flood mapping.     

Issues in the design of a parallel object-oriented language

This paper discusses the considerations that have played a role in the design of the language POOL2. This language integrates the structuring techniques of object-oriented programming with mechanisms for expressing parallelism. We introduce the basic principles of object-oriented programming and its significance for program development methodologies. Several approaches for integrating objects and parallelism are compared and arguments for the choices made in POOL2 are presented. We also explain why inheritance is not yet included in POOL2. A brief overview of the research in formal aspects of POOL is given. Finally we indicate some directions for future developments.     

Integration of legacy sub-system components into an object-oriented simulation model of a complete pastoral dairy farm

An object-oriented (OO) approach to developing a computer simulation of a complete pastoral dairy farm system is outlined. Since component models already existed which encapsulated the functionality of the high level objects in the overall system it was a primary design goal to be able to incorporate them into the OO framework. These components had been developed in procedural programming languages and techniques were investigated to incorporate them with little or no re-coding, and which allow them to be used in an ‘object-like’ way. The techniques involved recompilation of legacy source-code as dynamic link libraries (DLL's), and accessing stand-alone executable programs through inter-process communication (IPC) protocols. A cow metabolism model developed in the proprietary ACSL environment, and a pasture growth model for which FORTRAN source code was available were incorporated into the Smalltalk OO framework using the Microsoft Component Object Model (COM) techniques. Multiple instances of each component (each representing a distinct real farm entity) were required by the OO framework and the COM methodology was able to support this. The integration of these components into the host OO framework involved using proxy objects to provide translation to/from the COM messaging, thus providing the OO framework with consistent inter-object communication.     

An object-oriented multimedia database system for a news-on-demand application

We describe the design of a multimedia database management system for a distributed news-on-demand multimedia information system. News-on-demand is an application that uses broadband network services to deliver news articles to subscribers in the form of multimedia documents. Different news providers insert articles into the database, which are then accessed by users remotely, over a broadband, asynchronous transfer-mode (ATM) network. The particulars of our design are an object-oriented approach and strict adherence to international standards, in particular the Standard Generalized Mark-up Language (SGML) and Hy-Time. The multimedia database system has a visual query facility, which is also described in this paper. The visual query interface provides three major facilities for end users: presentation, navigation, and querying of multimedia news documents. The main focus, however, is the querying of multimedia objects stored in the database.     

Requirements for a new object-oriented methodology

Object-oriented components, such as languages, engines, persistent storages, and development environments, are not sufficient for developing high quality object-oriented applications. New formal methodologies, based on object-oriented concepts, also need to be developed that address all life cycle phases. A preliminary list of requirements for such an object-oriented methodology is proposed. From this new methodology, practical techniques and tools can be developed that increase productivity using the new object-oriented technologies.     

VB5.0在火山灾害信息系统用户界面设计中的应用

长白山火山是我国最具潜在喷发性危险的活火山之一，通过地理信息系统（GIS）对火山灾害信息进行管理，可以有效地进行火山灾害的监测、预测预报和分析评估。探讨了利用可视化编程语言Visual Basic 5.0设计长白山火山灾害信息系统数据库用户界面的方法和事件驱动机制，以期更好地实现数据库中数据对系统的支持。     

VB教学中“面向对象”思维的教学方法研究

《Visual Basic程序设计》作为计算机基础教育重要课程,其主要的目的是培养学员具备基本的简单编程能力。本文分析并讨论了VB编程有效的、快速的教学方法,使学员掌握＂面向对象＂程序设计的教学方法和技巧。     

High-accuracy simulation of orbital dynamics: An object-oriented approach

The use of Keplerian or Equinoctial parameters instead of Cartesian coordinates as state variables in object-oriented spacecraft models is introduced in this paper. The rigid body model of the standard MultiBody library is extended by adding transformation equations from Keplerian or Equinoctial parameters to Cartesian coordinates, and by setting the former as preferred states, instead of the latter. The remaining parts of the model are left untouched, thus ensuring maximum re-usability of the model itself. The results shown in the paper demonstrate the superior accuracy and speed of computation both in the case of a point-mass gravity field, and in the case of more accurate gravity field models.     

用智能数据采集模块开发数据监测系统

介绍了一种船舶机舱环境数据监测系统的层次结构和软件设计，采用I-7000系列模块完成了整个系统的现场数据采集及网络传输功能，应用Visual Basic设计了软件系统，实现了以太网同RS-485控制网络融合通信的功能，使得整个系统简单并具有良好的开放性。     

Model-based cache-aware dispatching of object-oriented software for multicore systems

In recent years, processor technology has evolved towards multicore processors, which include multiple processing units (cores) in a single package. Those cores, having their own private caches, often share a higher level cache memory dedicated to each processor die. This multi-level cache hierarchy in multicore processors raises the importance of cache utilization problem. Assigning parallel-running software components with common data to processor cores that do not share a common cache increases the number of cache misses. In this paper we present a novel approach that uses model-based information to guide the OS scheduler in assigning appropriate core affinities to software objects at run-time. We build graph models of software and cache hierarchies of processors and devise a graph matcher algorithm that provides mapping between these two graphs. Using this mapping we obtain candidate core sets that each software object can be affiliated with at run-time. These affiliations are determined based on the idea that software components that have the potential to share common data at run-time should run on cores that share a common cache. We also develop an object dispatcher algorithm that keeps track of object affiliations at run-time and dispatches objects by using the information from the compile-time graph matcher. We apply our approach on design pattern implementations and two different application program running on servers using CFS scheduling. Our results show that cache-aware dispatching based on information obtained from software model, decreases number of cache misses significantly and improves CFS’ scheduling performance.     

To model objects in information systems and user interfaces: implications for object-oriented methods

Abstract. A general way of contrasting the object-oriented to the function-oriented approach, called 'object-order' and 'function-order', is proposed in this paper. In addition, when modelling information systems, there is a third principle of ordering, 'subject-order'. Object and function-order are used to define the two approaches to modelling information systems and in human-computer interaction, in ways that are compatible to the corresponding distinction in programming. The conditions for selecting either of the two approaches are, however, not discussed here.
By means of an object-ordered method, e.g. Jackson System Development (JSD), an object-ordered model is produced, and the user interface that can be derived from the model is object-ordered too. However, other guidelines in JSD support subject-order. A function-ordered interface can be derived from the subject-ordered model. A computer system designed by means of an object-organized method may therefore obtain an interface that is partially object-ordered and partially function-ordered. Other object-oriented methods give guidelines for designing function-oriented interfaces without relating these guidelines to the model.
The system designer may benefit from having three principles of ordering when modelling a system. However, a user may be confused by an interface that sometimes gives preference to objects, sometimes to functions.     

MIS系统中不同数据平台数据集成技术的实现

本文针对MIS系统中不同数据平台数据的集成，在Ⅶ中通过OLE、DAO对象和ADO对象，从而实现不同数据平台之间的数据读取，为当前不同数据平台系统的集成提供了一种典型的解决方案。并给出了一个实例。     

An object-oriented database management system for computer-aided design of tall buildings

An effective database and database management system is the key to the success of an integrated approach to software engineering applications in general, and Computer-Aided Design (CAD) for structural applications in particular. Due to the inherent nature of CAD data such as dynamic modeling, a wide range of data types, large data volume, etc., the traditional database models, such as hierarchical, network and relational models, are unable to handle the aforementioned applications satisfactorily. An object-oriented data modeling is known to be the most effective approach. However, many of the commercial object-oriented databases are designed for information management, and they are inadequate for CAD application due to the different features of the object-hierarchy and varying data management objectives during the design cycles. This paper presents a hierarchical index-based object-oriented database management model for CAD applications. To deal with the object hierarchy encountered in CAD for the design of tall buildings, the proposed database consists of several salient features: a hierarchical object model, its related storage structure, a data dictionary, a class factory and an index system. The proposed database management model has been implemented into an integrated CAD system for design application of tall buildings.     

A modified Yule process to model the evolution of some object-oriented system properties

We present a model based on the Yule process, able to explain the evolution of some properties of large object-oriented software systems. We study four system properties related to code production of four large object-oriented software systems - Eclipse, Netbeans, JDK and Ant. The properties analysed, namely the naming of variables and methods, the call to methods and the inheritance hierarchies, show a power-law distribution as reported in previous papers for different systems. We use the simulation approach to verify the goodness of our model, finding a very good correspondence between empirical data of subsequent software versions, and the prediction of the model presented.